U.S. patent application number 10/278545 was filed with the patent office on 2004-04-22 for printhead maintenance system.
Invention is credited to Davis, Jeremy A., Harper, Kit L., Waller, David J..
Application Number | 20040075702 10/278545 |
Document ID | / |
Family ID | 32093418 |
Filed Date | 2004-04-22 |
United States Patent
Application |
20040075702 |
Kind Code |
A1 |
Waller, David J. ; et
al. |
April 22, 2004 |
Printhead maintenance system
Abstract
A system for receiving and recycling ink comprises a print
cartridge having a printhead, and an ink supply reservoir fluidly
connected to the print cartridge and a seal member coupled to the
ink supply reservoir. The seal member defines a fluid path into the
reservoir and the print cartridge engages the seal member so that
ink spit from the printhead flows through the fluid path into the
reservoir.
Inventors: |
Waller, David J.;
(Vancouver, WA) ; Davis, Jeremy A.; (Battle
Ground, WA) ; Harper, Kit L.; (Vancouver,
WA) |
Correspondence
Address: |
HEWLETT-PACKARD COMPANY
Intellectual Property Administration
P.O. Box 272400
Fort Collins
CO
80527-2400
US
|
Family ID: |
32093418 |
Appl. No.: |
10/278545 |
Filed: |
October 22, 2002 |
Current U.S.
Class: |
346/36 ; 346/86;
347/35 |
Current CPC
Class: |
B41J 2/16547
20130101 |
Class at
Publication: |
346/036 ;
347/035; 346/086 |
International
Class: |
B41J 002/165; G01D
009/00; G01D 015/04; G01D 015/20 |
Claims
1. A method for maintaining a printhead, comprising the steps: (a)
supplying ink to a printhead from an ink supply reservoir; (b)
positioning the printhead adjacent the ink supply reservoir; and
(c) spitting ink from the printhead into the ink supply
reservoir.
2. The method of claim 1 wherein the printhead is disposed in a
print cartridge, the method including the step of establishing a
sealing engagement between the pen and the ink supply
reservoir.
3. The method of claim 2 including the step of filtering
contaminants from ink spit from the printhead into the ink supply
reservoir.
4. The method of claim 3 wherein the step of filtering contaminants
comprises positioning a filter between the printhead and the ink
supply reservoir.
5. The method of claim 1 including the steps of (a) supplying ink
to plural printheads from a separate ink supply reservoir
associated with each printhead; (b) positioning each printhead
adjacent a respective one of the separate ink supply reservoirs;
and (c) spitting ink from selected ones of the printheads into the
respective one of the separate ink supply reservoirs.
6. The method of claim 1 including the step of scraping ink from
the printhead with a wiper blade.
7. A system for receiving and recycling ink, comprising: print
cartridge having a printhead; an ink supply reservoir; a fluid
conduit interconnecting the ink supply reservoir to the print
cartridge; a seal member coupled to the ink supply reservoir and
defining a fluid path into the reservoir, the print cartridge
configured for engaging the seal member so that ink spit from the
printhead flows through the fluid path into the reservoir.
8. The system of claim 7 wherein the seal member further comprises
an elastomeric cap defining walls configured for engaging
cooperatively formed walls on the pen, and the seal member further
defines the fluid path into the reservoir.
9. The system of claim 7 including a filter in the fluid path.
10. The system of claim 9 wherein the filter is interposed in the
fluid path between the seal member and the ink supply
reservoir.
11. The system of claim 7 including a wiper blade positioned for
scraping ink from the printhead.
12. The system of claim 7 including a pump in the fluid conduit
operable to pump ink contained in the ink supply reservoir to the
print cartridge.
13. The system of claim 7 including an actuator coupled to the ink
supply reservoir and configured for selectively moving the ink
supply reservoir into and out of a fluidly sealed engagement with
the print cartridge.
14. The system of claim 13 wherein the actuator further comprises a
driving means for selectively moving the ink supply reservoir into
and out of the fluidly sealed engagement with the print
cartridge.
15. The system of claim 10 wherein the filter further defines a
plug for preventing loss of ink from the ink supply reservoir
through the fluid path.
16. A system for receiving and recycling ink, comprising: plural
print cartridges, each print cartridge in the plurality having a
printhead associated therewith; plural ink supply reservoirs, each
ink supply reservoir in the plurality associated with a print
cartridge; plural fluid conduits, each conduit in the plurality
interconnecting an ink supply reservoir with the associated print
cartridge; plural seal members, each seal member in the plurality
coupled to an associated ink supply reservoir and each seal member
defining a fluid path into the associated reservoir, wherein each
print cartridge in the plurality is configured for engaging an
associated seal member so that ink spit from the printhead flows
through the fluid path into the reservoir.
17. The system of claim 16 wherein each of the plural seal members
further comprises an elastomeric cap defining walls configured for
engaging cooperatively formed walls on the associated pen, and each
of the plural seal members further defines the fluid path into the
associated reservoir
18. The system of claim 17 wherein the plural seal members further
comprise a one piece elastomeric cap.
19. A method of maintaining a printhead, comprising the steps of:
(a) supplying ink to a printhead from an ink supply reservoir,
wherein the ink supply reservoir defines a capping member having a
fluid pathway therethrough to the supply of ink; (b) moving a print
cartridge housing the pen into a sealing engagement with the
capping member so that the printhead is in fluid communication with
the supply of ink.
20. The method of claim 19 including the step of causing the
printhead to expel ink while the print cartridge is in the sealing
engagement with the capping member so that the ink expelled from
the printhead flows into the ink supply reservoir.
21. The method of claim 20 including the step of removing
contaminants from the ink expelled from the printhead.
22. The method of claim 21 wherein contaminants are removed from
the ink expelled from the printhead with a filter in the fluid
pathway.
23. A maintenance system for capping a printhead, comprising: a
print cartridge having the printhead; an ink supply reservoir
coupled to the print cartridge with a conduit; a pen cap on the ink
supply reservoir, the pen cap defining a fluid path into the ink
supply reservoir and defining a seat configured to receive the
print cartridge and to define a seal between the print cartridge
and the pen cap.
24. The maintenance system of claim 23 wherein ink expelled from
the printhead flows through fluid path and into the ink supply
reservoir.
25. The maintenance system of claim 24 wherein the ink expelled
from the printhead is reintroduced to the printhead through the
conduit.
26. The maintenance system of claim 25 including a filter
interposed in the fluid pathway.
27. The maintenance system of claim 23 including a wiping blade for
scraping ink from the printhead.
28. A system for receiving and recycling ink, comprising: a print
cartridge having a printhead; an ink supply reservoir; a fluid
conduit interconnecting the ink supply reservoir to the print
cartridge; seal member means coupled to the ink supply reservoir
and defining a fluid path into the reservoir, the print cartridge
configured for engaging the seal member means so that ink spit from
the printhead flows through the fluid path into the reservoir.
29. The system of claim 28 wherein the seal member means further
comprises flexible cap means defining walls configured for engaging
cooperatively formed walls on the pen.
30. The system of claim 29 wherein the seal member means further
comprises fluid path means into the reservoir.
31. The system of claim 30 further comprising filter means in the
fluid path means.
32. The system of claim 28 including pump means in the fluid
conduit for pumping ink contained in the ink supply reservoir to
the print cartridge.
33. The system of claim 28 including actuator means coupled to the
ink supply reservoir for selectively moving the ink supply
reservoir into and out of a fluidly sealed engagement with the
print cartridge.
34. The system of claim 28 wherein the actuator means further
comprises driving means for selectively moving the ink supply
reservoir into and out of the fluidly sealed engagement with the
print cartridge.
Description
BACKGROUND OF THE INVENTION
[0001] Inkjet printheads require regular servicing in order to
maintain the printheads and the quality of print jobs. Although
there are many types of servicing systems and service stations,
three pen service procedures involve wiping, spitting and capping.
Wiping is a process by which the printhead nozzles are engaged with
a scraper, typically rubber, to clean accumulated ink and debris
off the nozzles. Spitting is a step that involves positioning the
printheads over a waste ink receptacle--a spittoon--and causing the
inkjet printhead to eject a volume of ink through the nozzles into
the spittoon. Spittoons are simply receptacles that collect the
waste ink. Sometimes spittoons are lined with absorbent material to
retain the waste ink. Capping involves positioning the printheads
in physical contact with a closely fitting cap--typically rubber or
some other elastomer--to maintain a controlled atmosphere
environment around the printheads during periods of inactivity.
[0002] Many inkjet printer service stations are configured for
performing each of these three servicing tasks, and there are many
variations in the order and frequency of the three servicing tasks.
However, printhead servicing does not address issues relating to
ink supply for the pen.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] FIG. 1 is a schematic front view of selected components of
an inkjet printer according to an embodiment of the present
invention, illustrating the inkjet pens laterally adjacent the ink
supply and with the pens positioned as they would be during
printing operations.
[0004] FIG. 2 is a schematic front view of the inkjet printer shown
in FIG. 1 with the inkjet pens parked in the service station
according to an embodiment of the present invention.
[0005] FIG. 3 is a partial fragmentary view of the inkjet pens
parked in the service station according to an embodiment of the
present invention taken at the close up circle 3 in FIG. 2.
[0006] FIG. 4 is a sectional view of a single inkjet pen as it is
parked in the service station according to an embodiment of the
present invention taken along the line 4-4 of FIG. 3.
[0007] FIG. 5 is a schematic front view of an inkjet printer
similar to the printer shown in FIG. 1, illustrating an alternate
embodiment of the present invention in which the printhead seal
member is fabricated in a single piece.
[0008] FIG. 6 is a partial fragmentary view of the inkjet pens
shown in FIG. 5 parked in the service station according to the
embodiment, taken at the close up circle 6 of FIG. 5.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0009] Many hardcopy devices that rely upon inkjet printing
technology include service stations for maintaining the quality of
the printheads, and thus the quality of the print jobs. A schematic
representation of an inkjet printer according to an illustrated
embodiment of the present invention is shown in the drawings. It
will be appreciated that like reference numerals are used
throughout the specification to identify like structural features
found in more than one drawing figure.
[0010] With reference to FIGS. 1 and 2, the inkjet printer 10
depicts in a highly schematic manner an inkjet hard copy apparatus,
in this case, a color printer. It will be appreciated that printer
10 includes numerous electrical and mechanical operating mechanisms
that are necessary to operation of the printer, but not needed to
illustrate the components or invention described herein. As such,
many electrical and mechanical operating mechanisms are omitted
from the drawings for clarity. An internal electronic controller
90, which is usually a microprocessor or application specific
integrated circuit ("ASIC") controlled printed circuit board,
administrates operation of inkjet printer 10, which is connected by
appropriate cabling to an external computer (not shown). It is well
known to program and execute imaging, printing, print media
handling, control functions, and logic with firmware or software
instructions for conventional or general purpose microprocessors or
ASICs. Print media 12 (referred to generically herein simply as
"paper," regardless of actual medium selected by the end-user, for
example, cut sheet or roll stock material such as paper, film, and
the like) is loaded by the end-user onto an input tray (not shown).
Sheets of paper are then sequentially fed by a suitable, internal,
paper-path transport mechanism to a printing station that defines a
printzone 14 where graphical images or alphanumeric text are
created using color imaging and text rendering techniques. In FIG.
1, printzone 14 is defined generally as the area beneath the region
traversed by the inkjet print cartridges 20, 22, 24 and 26 where
ink is applied to the paper 12.
[0011] A carriage 16 mounted on a shaft 18 that has its opposite
ends mounted to a printer chassis 19 to support in an operative
position relative to paper 12 a set of four inkjet writing
instruments, known as print cartridges, and labeled 20, 22, 24, and
26, respectively. Fewer print cartridges or more print cartridges
may be used in different printers. As detailed below, each of the
inkjet print cartridges 20 through 26 has at least one printhead 28
on the lower side of the print cartridges facing the printzone 14.
Each printhead 28 is adapted for expelling minute droplets of ink
or other fluids to form dots on adjacently positioned paper 12 in
the print zone 14. Each printhead 28 generally consists of a drop
generator mechanism and a number of columns of ink drop firing
nozzles. Each column of nozzles, or a selected subset of nozzles,
selectively fires ink droplets, each droplet typically being only a
tiny liquid volume, that are used to create a predetermined print
matrix of dots on the adjacently positioned paper as the printhead
is scanned across the media. A given nozzle of the printhead is
used to address a given matrix column print position on the paper.
Horizontal positions, matrix pixel rows, on the paper are addressed
by repeatedly firing a given nozzle at matrix row print positions
as the pen is scanned across the paper. Thus, a single sweep scan
of the printhead across the paper can print a swath of dots. The
paper is advanced incrementally relative to the inkjet printheads
to permit a series of contiguous swaths.
[0012] Inkjet printer 10 is shown as a full color inkjet system and
therefore includes inks for the subtractive primary colors, cyan,
yellow, magenta (CYM) and a true black (K). By way of example,
print cartridge 20 contains cyan ink, print cartridge 22 yellow
ink, print cartridge 24 magenta ink, and print cartridge 26 black
ink. Different or additional colorants, such as, for example,
lighter or darker shades of magenta and/or cyan, may of course be
used. While the illustrated color print cartridges 20, 22, and 24
each use a dye-based ink, other types of inks may also be used,
such as paraffin-based inks, as well as hybrid or composite inks
having both dye and pigment characteristics.
[0013] Carriage 16 and thus print cartridges 20, 22, 24 and 26 are
mounted on shaft 18 for shuttle-type reciprocating movement over
media 12. Shaft 18 and carriage 16 are mounted on printer chassis
19. A carriage motor 21, typically a servo motor that is connected
via circuitry 25 to controller 90 and to carriage 16 with a drive
belt 27 (illustrated schematically), moves or "scans" carriage 16
during printing in a back and forth direction transverse to the
direction of media advancement through the printzone 14. It is
common in the art to refer to the scanning direction as the x-axis,
the paper feed direction through the printzone as the y-axis, and
the ink drop firing direction as the z-axis. That convention is
used herein.
[0014] As noted, carriage 16 is under the control of the printer
controller 90. The position of carriage 16 relative to paper 12 in
the direction along the x-axis is determined by way of an encoder
strip 23 that has its opposite ends mounted to the printer chassis
19. The encoder strip 23 extends past and in close proximity to an
encoder or optical sensor (not shown) carried on carriage 16 to
thereby signal to the printer controller 90 the position of the
carriage assembly 16 relative to the encoder strip 23.
[0015] The paper 12 is incrementally advanced through the printzone
14 by a paper transport mechanism (not shown), typically in-between
scans of the carriage 16. An encoder, typically a disk encoder, and
associated servo systems are one of the methods often employed for
controlling the precise incremental advance of the media. This
incremental advance is commonly called "linefeed." Precise control
of the amount of the advance, the linefeed distance, contributes to
high print quality. The paper advance mechanisms must move the
paper 12 through the printzone 14 the desired distance with each
incremental advance, at the desired rate, and so that the paper is
oriented correctly relative to the printheads 28.
[0016] Each illustrated print cartridge 20, 22, 24 and 26 is
individually coupled to a respective ink supply main reservoir 30,
32, 34 and 36, by separate flexible ink delivery tube or other
conduit 40, 42, 44 and 46, respectively, in what is known as an
"off axis" ink delivery system. An off axis system may be
contrasted with a replaceable, self-contained ink delivery system
where each print cartridge has a reservoir that carries the entire
ink supply as it reciprocates along the x-axis, and is thus called
an "on axis" delivery system. Each pen 20 through 26 includes an
on-board reservoir or chamber for holding a volume of ink that is
typically smaller than the volume of ink contained in the main
reservoirs 30 through 36. The main reservoirs 30 through 36 are
typically replaceable ink-in-foam or spring-in-bag designs, but
other reservoir designs may also be used.
[0017] A service station shown generally and schematically in
dashed lines at 50 services the printheads 28 associated with each
of the pens 20, 22, 24 and 26. Service station 50 includes a pen
wiper station 52 and printhead seal members 60, 62, 64 and 66. As
detailed below, printhead seal members 60 through 66 are components
of the ink supply main reservoirs 30 through 36. Wiper station 52
is positioned relative to pens 20 through 26 such that when the
printer controller 90 causes carriage 16 to move along the x-axis
in the direction of arrow A in FIG. 1, the printheads are dragged
across wiper blades 58 (three of which are illustrated) to effect
cleaning of the printheads 28. The wiper blades 58 physically
scrape ink and contaminants off the printheads 28. Wiper station 52
may be either stationary, or may be configured to move into an out
of an operative position, typically by movement with an actuating
mechanism in the direction along either the z or y-axes.
[0018] The ink supply main reservoirs 30, 32, 34 and 36 may be used
as components of the service station 50. That is, the main supply
reservoirs 30 through 36 may be used to receive ink directly from
the printheads 28 of the print cartridges 20 through 24, recycle
ink spit during servicing, and cap the printheads 28 during
storage, in addition to supplying ink to the printheads 28. It will
be appreciated that because the main ink supply reservoirs 30
through 36 are located in the illustrated embodiment below the pens
20 through 26, it may be necessary in some circumstances to include
an optional pump and appropriate valves and/or sensors, illustrated
generally with reference number 41, to assist with delivery of ink
through conduits 40 through 46 from ink supply main reservoirs 30
through 36 to the associated pens 20 through 26. Conduits 40
through 46 are typically flexible tubing.
[0019] As may be seen in FIG. 2, and as will be detailed below,
when pens 20 through 26 are being serviced and/or stored, the pens
are brought into contact with a printhead seal members 60 through
66, respectively. An actuating system 33, which is shown
schematically but understood to include driving means such as a
motor and appropriate linkages, is provided to move ink supply main
reservoirs 30 through 36 into and out of coupling engagement with
printheads 28, in the directions indicated with arrows B in the
figures.
[0020] With reference now to FIG. 3, each ink supply main reservoir
30 through 36 includes a printhead seal member 60, 62, 64 and 66,
respectively, on the upper surface of the reservoir ("upper
surface" referring to the surface of the reservoir facing print
cartridges 20 through 26). Thus, printhead seal member 60 is
associated with main reservoir 30; printhead seal member 62 is
associated with main reservoir 62, and so on. The printhead seal
members 60 through 66 are elastomeric capping members--typically
fabricated of nitrile rubbers, elastomeric silicones, ethylene
polypropylene diene monomer (EPDM) and equivalent compounds--that
are configured to engage a respective one of the printheads 28 on
the print cartridges 20 through 26 to provide a fluid seal with the
printheads, and to provide a desirably humid storage environment
for maintaining printhead integrity, and as detailed below, for
facilitating recycling of ink spit from the printheads 28.
[0021] A single print cartridge, ink supply reservoir and printhead
seal are illustrated in FIG. 4, in this case, pen 20 and the
components associated therewith. Print cartridge 20 is
schematically illustrated as defining a hollow ink-holding
reservoir, internal chamber 69, for holding a supply of ink 71 that
may be expelled through printhead 28. Printhead 28 is illustrated
schematically for the sake of simplicity, and is understood to be
under the control of controller 90. Printhead 28 generally includes
a plurality of drop generators 73, typically thin film resistors
that cause ink to be expelled in a controlled manner through
corresponding ink drop firing nozzles 72. The outer wall of print
cartridge 20 defines an outer peripheral wall 74 that borders and
surrounds printhead 28. The outer surfaces of peripheral wall 74
are configured to form a seal with complementary wall surfaces of
printhead seal member 60. One such arrangement is shown in FIG. 4
where the outer mating surfaces of peripheral wall 74 slope or
taper inwardly, and the corresponding mating walls 76 of the
printhead seal member 60 slope or taper correspondingly and in a
complementary manner so that the respective walls 74, 76 mate to
one another and form a seal therebetween.
[0022] Referring specifically to FIG. 4, printhead seal member 60
is located atop ink supply reservoir 30 and defines a capping
member having interior wall surfaces that are cooperatively
configured and shaped to engage the corresponding outer peripheral
wall 74 of print cartridge 20. Thus, the inward-facing surfaces of
member 60 define a first downwardly sloping wall section 76 that
tapers inwardly and which is configured at an angle that is
complimentary to the taper of outer peripheral wall 74 of print
cartridge 20 such that when the supply reservoir 30 is moved into
the position where seal member 60 engages print cartridge 20, as
shown in FIG. 4, a fluid-tight seal is formed between the print
cartridge 20 and the printhead seal member 60. Printhead seal
member 60 includes a second downwardly sloping wall section 78
interiorly of wall section 76. Thus, with reference to the
direction in FIG. 4 moving from first downwardly sloping wall
section 76 toward the center portion of the seal member 60, the
second downwardly sloping wall section 78 terminates at an opening
80 that communicates through the seal member 60 into supply
reservoir 30 to define a fluid path 77 from print cartridge 20 to
ink 70 held in reservoir 30. A filter 82 is positioned within
reservoir 30 in the fluid path. The printer controller 90 and
actuator 33 cooperate to move reservoir 30 in the direction
indicated by arrows B in order to move the reservoir 30 into a
sealing relationship between the printhead seal member 60 and the
printhead 28 as shown.
[0023] When the printer controller 90 determines that a printhead
28 needs to spit to maintain the health of nozzles 72, or for some
other reason servicing is required, the controller 90 causes
carriage 16 to be positioned relative to the ink supply reservoirs
30 through 36 such that the printheads 28 are aligned over the
corresponding printhead seal members 60, 62, 64 and 66. When the
print cartridges 20 through 26 and their associated printheads 28
and the associated printhead seal members 60 through 66 are
aligned, controller 90 causes carriage motion to stop, and the
controller 90 and actuator 33 cooperate to move reservoirs 30
through 36 upwardly as indicated with arrow B in FIG. 4 until each
of the printhead seal members 60 through 66 are in the position
shown in FIG. 4. In this position a fluid-tight seal is formed
between each of the print cartridges 20 through 26 and the
associated printhead seal members 60 through 66. It should be noted
that while in most instances the physical engagement between the
printhead seal members 60 through 66 and the corresponding
printheads 28 provides a fluid tight sealed engagement
therebetween, spitting may be accomplished with the printheads 28
and printhead seal members 60 through 66 in close proximity to one
another rather than in a sealed relationship. The controller 90
then causes ink to be spit by the selected printhead nozzles 72
into printhead seal member 60.
[0024] Ink 71 spit from printhead 28 is illustrated schematically
in FIG. 4 with dotted lines 84. The first and second downwardly
sloping walls 76 and 78 of the printhead seal member 60 cause the
ink 71 to flow into opening 80, through fluid path 77, through a
filter 82 and into the supply of ink 70 contained in main reservoir
30. Any contaminants carried by the ink 70 or introduced from other
sources are captured by the filter 82 and are therefore prevented
from entering the supply of ink 70 or delivery conduit 40. Spit ink
71 from pen 20 is thus mixed with ink 70 residing in the supply
reservoir 30 and is recycled since it is again available to be
drawn into delivery conduit 40 and reintroduced into chamber 69 of
print cartridges 20. The controller 90 is configured for initiating
spitting for any of the printheads on an individual basis, or for
all of the printheads together. During the periods of time when the
pens are separated from the printhead seal members, as for example
during active printing operations, filter 82 serves as a plug or
seal that retards any evaporation of ink 70 from the supply
reservoir 30.
[0025] By recycling the ink in the manner just described, overall
consumer ink costs are reduced and the printer need not be taken
out of service to eliminate waste ink in a spittoon. Moreover, the
mess associated with waste ink in spittoons, and possible
environmental consequences of throwing out waste ink, are
eliminated. And by eliminating the hardware associated with
spittoons and the associated mechanisms, valuable space in the
printer housing are freed up for other components, or for reduction
in the size and cost of the printer. Finally, since the print
cartridges 20 through 26 are brought into a sealing engagement with
the printhead seal members 60 through 66 when spitting occurs, any
ink aerosolized during spitting is recycled, eliminating the risk
that ink thus expelled from one printhead 28 may cross contaminate
adjacent printheads 28.
[0026] After spitting as described above, the print cartridges 20
may return to printing, undergo other servicing, or be capped for
storage. It will be appreciated that in the case where the print
cartridges 20 through 26 are to be stored after spitting, then the
sealing engagement described above between print cartridges 20
through 26 and printhead seal members 60 through 66 is maintained.
When the print cartridges 20 through 26 and their associated
printheads 28 are to be stored between periods of printing, the
carriage 16 and print cartridges 20 through 26 are positioned over
the ink supply reservoirs 30 through 36 as shown in FIG. 1.
Controller 90 in cooperation with actuator 33 moves supply
reservoirs 30 through 36 upwardly (in the direction of the z-axis
indicated with arrows B) so that the printhead seal members 60
through 66 are brought into contact with the print cartridges 20
through 26 as previously described. The sealing engagement between
the print cartridges 20 through 26 and the associated printhead
seal members 60, 62, 64 and 66 creates a controlled environment
around the printhead nozzles that helps maintain printhead health.
Specifically, when the print cartridges 20 through 26 are in a
sealing engagement with the seal members 60 through 66, which
communicate via openings 80 and fluid paths 77 with a large
reservoir of ink 70 contained in the main reservoirs 30 through 36,
as shown and described, the ambient pressure and humidity
conditions surrounding the printhead 28 during storage are
favorable and promote long printhead life. Thus, the humidity is
controlled around the printheads 28 not only by the ink present in
the nozzles 72, but also by the fluid communication with the
relatively large reservoir of supply ink 70. The desirable humid
environment thus created and maintained helps to reduce ink
thickening at the nozzles. Finally, during storage, ink is often
and inevitably drooled from a printhead 28. When the printheads 28
are capped as described above with printhead seal members 60
through 66, drooled ink flows back into the ink supply reservoirs
through openings 80 where it is recycled in the same manner as ink
that is intentionally spit from the nozzles 72.
[0027] In the embodiment illustrated in FIGS. 1 through 4, each ink
supply reservoir 30 through 36 includes a separate printhead seal
member, 60 through 66, which seals over a separate printhead 28 on
an associated pen 20 through 26. It will be appreciated that the
printhead seal members may be fabricated in a single piece. An
alternate embodiment of the invention showing a single piece
printhead seal member is illustrated in FIGS. 5 and 6. With
reference to those drawings, the individual printhead seal members
60 through 66 have been replaced with a single printhead seal
member 100 that is fabricated to fit atop each of the four ink
supply main reservoirs 30 through 36. Apart from being fabricated
in a single piece that engages all of the ink supply main
reservoirs, printhead seal member 100 is substantially the same as
the individual printhead seal members 30 through 36 as detailed
above. As shown in the partial fragmentary view of FIG. 6,
printhead seal member 100 defines four capping members, one for
each of the printheads 28 associated with pens 20 through 26.
Because the seal member 100 is fabricated in a single piece, a
partition 102 is provided between adjacent pens, such as the
partition 102 between pens 20 and 22 shown in FIG. 6. Partition 102
is fabricated as an integral part of seal member 100.
[0028] It will be appreciated that single-piece printhead seal
member 100 may be used in a printer that utilizes more or less pens
than the four illustrated herein.
[0029] The ink supply reservoirs 30 through 36 are replaceable. The
printhead seal members may be fabricated such that they are
replaced when the ink supply reservoirs are replaced, or the seal
members may be reused on the replacement reservoirs if desired. The
printhead seal members may thus be made as replaceable consumable
components, as reusable components, or as permanent components or
any combination.
[0030] Although preferred and alternative embodiments of the
present invention have been described, it will be appreciated by
one of ordinary skill in this art that the spirit and scope of the
invention is not limited to those embodiments, but extend to the
various modifications and equivalents as defined in the appended
claims.
* * * * *